鸡白痢沙门菌减毒活疫苗候选株SKLZΔspiC对非靶动物(鼠)的致病性

Pathogenicity of live attenuated Salmonella pullorum vaccine candidate strain SKLZΔspiC to non-target animals(mice)

目的评价鸡白痢沙门菌减毒活疫苗候选株SKLZΔspiC对非靶动物(鼠)的致病性。方法采用鸡白痢沙门菌减毒活疫苗候选株SKLZΔspi C[1×10~7、1×10~9 CFU/(0. 1 mL·只)]及鸡白痢沙门菌S06004(Nal^R)[1×10~7 CFU/(0. 1 mL·只)],分别经肌肉注射和口服感染小鼠,同时设空白对照组(未感染)。观察小鼠的临床症状、病理、体重、脏器内菌体载量、粪便排菌及脾脏细胞因子水平,分析鸡白痢沙门菌减毒疫苗候选株对小鼠的致病性。结果与空白对照组比较,各组小鼠均未出现任何临床症状,肝脏、脾脏、盲肠病理观察均未见任何病变,体重变化差异无统计学意义(P> 0. 05)。与鸡白痢沙门菌S06004(Nal R)感染组比较,减毒活疫苗候选株感染组小鼠肝脏、脾脏、盲肠内及小鼠粪便载菌量均降低。各感染组小鼠脾脏中炎性因子IL-1β、IFNγ、IL-12、IL-6表达量均较低,仅引起小鼠轻微短暂的炎症反应。结论鸡白痢沙门菌减毒疫苗候选株SKLZΔspiC对非靶动物(鼠)无致病性,符合公共卫生安全要求。

Objective To evaluate the pathogenicity of live attenuated Salmonella pullorum vaccine candidate strain SKLZΔspiC to non-target animals(mice). Methods Mice were infected with S. pullorum SKLZΔspiC strain at dosages of 1×10^7 and 1×10^9 CFU/0.1 mL and its parent strain S06004(Nal^R)at a dosage of 1×10^7 CFU/0.1 mL by intramuscular and oral routes separately,using those uninfected as control. The clinical symptoms,pathological changes,bodyweights,bacterial loads in liver,speen and cecal,fecal excretion and splenic inflammatory cytokines of mice were observed to analyze the pathogenicity of SKLZΔspiC strain to mice. Results Compared with those in blank control group,no any clinical symptoms were observed in mice in various test groups,and no any lesions in the histopathology of liver,speen and cecal,while the bodyweight showed no significant change(P > 0. 05). However,compared with those infected with strain S06004(Nal R),the bacterial loads in liver,speen and cecal as well as fecal excretion of mice infected with SKLZΔspiC strain decreased. The expression levels of IL-1β,IFNγ,IL-12 and IL-6 in various test groups were low,which caused only mild and transient inflammatory reactions. Conclusion Live attenuated S. pullorum vaccine candidate strain SKLZΔspiC showed no pathogenicity to non-target animals(mice),which met the requirements of public safety.